The experiments will explore the effects of prior Pavlovian conditioning operations upon the acquisition, performance, and persistence of instrumental responding -- primarily avoidance responding. Emphasis will be placed upon the elucidation of the mechanisms whereby the Pavlovian stimuli exert their control. The initial contrast will be between motivational and associative/cue mechanisms. It is hoped that this research will contribute to our understanding of basic learning processes and behavioral laws of avoidance-like behaviors in general, and thus to a better understanding of the role acquired emotional reactions play in the development, control, and maintenance of phobic/compulsive neurotic behaviors.